Best IoT Learning Path for College Dropouts

// temperature_logger.ino — Phase 1, Week 5–6
// Reads a DHT11 temperature sensor and prints to the serial monitor.
// This is the first real IoT-style project most beginners build.

#include <DHT.h>

#define DHTPIN 2
#define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  dht.begin();
  Serial.println("Temperature Logger — starting");
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("Sensor read failed — check wiring");
    delay(2000);
    return;
  }

  Serial.print("Temp: ");
  Serial.print(temperature);
  Serial.print(" C | Humidity: ");
  Serial.print(humidity);
  Serial.println(" %");

  delay(2000);
}

// What you learn here:
// - How to wire a sensor correctly (VCC, GND, data pin)
// - Why sensors sometimes return NaN
// - How to log data over serial for debugging
// - The foundation for publishing data to a cloud later

# read_sensor.py — Phase 2, Week 9–10
# Reads a sensor on a Raspberry Pi and writes values to a CSV file.
# The bridge between hardware and software.

import time
import csv
from datetime import datetime

try:
    import board
    import adafruit_dht
except ImportError:
    print("Install dependencies: pip install adafruit-circuitpython-dht")
    raise

sensor = adafruit_dht.DHT11(board.D4)
OUTPUT = "sensor_log.csv"

def read_once():
    try:
        temperature = sensor.temperature
        humidity = sensor.humidity
        return temperature, humidity
    except RuntimeError as e:
        print(f"Read error: {e}")
        return None, None

def main():
    with open(OUTPUT, "a", newline="") as f:
        writer = csv.writer(f)
        writer.writerow(["timestamp", "temperature_c", "humidity_pct"])

        for _ in range(20):
            temp, hum = read_once()
            if temp is not None:
                writer.writerow([datetime.now().isoformat(), temp, hum])
                print(f"{temp}C, {hum}%")
            time.sleep(2)

if __name__ == "__main__":
    main()

# What you learn here:
# - Reading real hardware from Python
# - Logging to CSV for later analysis
# - Why sensor reads sometimes fail and how to handle it
# - The pattern you will reuse in every IoT project

# mqtt_publish.py — Phase 2, Week 13–14
# Publishes sensor data to an MQTT broker so any dashboard can subscribe.
# This is the core pattern of a connected IoT device.

import json
import time
import random
import paho.mqtt.client as mqtt

BROKER = "broker.hivemq.com"
PORT = 1883
TOPIC = "uncodemy/iot/demo/sensor"

client = mqtt.Client()
client.connect(BROKER, PORT, 60)
client.loop_start()

try:
    while True:
        payload = {
            "device_id": "sensor-001",
            "temperature_c": round(24 + random.uniform(-2, 2), 2),
            "humidity_pct": round(60 + random.uniform(-5, 5), 2),
            "timestamp": int(time.time()),
        }
        client.publish(TOPIC, json.dumps(payload))
        print("published:", payload)
        time.sleep(3)
except KeyboardInterrupt:
    print("stopping")
finally:
    client.loop_stop()
    client.disconnect()

# What you learn here:
# - How MQTT works (publish / subscribe)
# - Why JSON is the standard IoT payload format
# - How to attach a real device to a real broker
# - The pattern used by every cloud-connected sensor